Mr Jahan said his family had been denied justice after it was revealed senior police officers made unauthorised offers of immunity to suspects without informing defence counsel.

The IPCC concluded there was “no case to answer” for misconduct against the man who led the murder investigation, Det Chief Insp Anthony Tagg, but said the family liaison officer, Det Insp Khalid Kiyani, “would have had a case to answer for gross misconduct”.

Speaking about the report, Mr Jahan, a delivery driver, said: “I had just lost my son and the police were using me to quell the riots. I expected to get justice and all I got was a slap in the face from the justice system.”

The IPCC launched its inquiry into West Midlands Police’s handling of the murder investigation and specifically the conduct of the two detectives in the case.

The IPCC added the CPS had since concluded there was “insufficient evidence to provide a realistic prospect of proving that either police officer had knowingly made a false statement and as a result committed the offence of perjury”.